Yes the 4.2 player models have changed and are different from the 4.1 versions. A known issue with the 4.1 models is they were built 12.5% under scale and code was added to scale up the models to the full 72 units as to what they needed to be.

In 4.2 player models were properly scaled and the scale code removed that was causing a side effect to collision detection.

The fix for now is to eyeball added funstuff and move the object around relative to the tag_head until it fits. Yes a bit of a pain but with out seeing the scene file you might have to scale up 12.5% as the old heads were based on the 62 unit player models and then the funstuff upscale in code to fit the then player models.